Restrict length of repo description on repolist page

If any repo has a very long description, all repos suffer since the
repo-links in the right-most column gets pushed out of sight.

Fix it by introducing max-repodesc-length parameter in cgitrc, and default
to 60 chars.

Signed-off-by: Lars Hjemli <hjemli@gmail.com>

shared.c

@@ -30,6 +30,7 @@ int cgit_cache_static_ttl      = -1;
 int cgit_cache_max_create_time =  5;
 
 int cgit_max_msg_len = 60;
+int cgit_max_repodesc_len = 60;
 int cgit_max_commit_count = 50;
 
 int cgit_query_has_symref = 0;
@@ -118,6 +119,8 @@ void cgit_global_config_cb(const char *name, const char *value)
 		cgit_cache_dynamic_ttl = atoi(value);
 	else if (!strcmp(name, "max-message-length"))
 		cgit_max_msg_len = atoi(value);
+	else if (!strcmp(name, "max-repodesc-length"))
+		cgit_max_repodesc_len = atoi(value);
 	else if (!strcmp(name, "max-commit-count"))
 		cgit_max_commit_count = atoi(value);
 	else if (!strcmp(name, "repo.url"))